Grinding wheel for bristles



GRINDING WHEEL -FoR BRIsTLEs Filed May 28, 1935 Patented Oct. 15, 1935 NITED STATES 2,017,487 GRINDING WHEEL FR BRISTLES William S. Elliot, Northampton, Mass., assigner to Pro-Phy-Lac-Tic Brush Company, Northampton, Mass., incorporation of Delaware Application May zo, 193s, senat No. 23,858 i claim. (citi-zoe) handle or heel end of the bristle body and that This invention relates to a grinding wheel for use in grinding the ends of bristles or similar articles so that they will have a rounded shape approaching the found that when bristles in brushes are trimmed to give the brush the proper contour, sharp, jagged edges, splinters and needle like fragments are formed on the ends of the bristles and that to provide means which will grind simultaneously device described herein is found to be more satis- In the accompanying drawing, I have shown a grinding wheel adapted to round the bristles of 2 a brush which is trimmed to the. well known at the tip of the bristle body which is longer than the rest of the surface and the remainder of the bristle body is provided with a series of pointed tufts which increase slightly in length toward the handle end of the bristle body.

Fig. 1 is an end view of a grinding wheel embodying my invention.

Fig. 2 is a. side elevation of the grinding wheel shown in Fig. 1. Fig. 3 is a,Y section on line 3 3 looking in the direction of the arrows.

Figs. 4, 5, 6, 7 and 8 are sections takenat points I, 5, 6, 1 and 8 as indicated in Fig. 3 and showing the successive positions occupied by two tufts of bristles as the grinding wheel revolves.

Fig. 9 is an enlarged view of one end of a bristle which has been ground by a wheel embodying my invention.

the grinding surface.

Referring now to Fig. 2 there is shown in elevation the head of a tufted tooth brush, the head being shown at a, the portion of the handle at b, the knots of bristles c, c forming the' end tuft d and the other knots oi' bristles e, e forming the remainder of the bristle body of the brush. It will be noticed that these tufts are longer at the hemispherical. It has beenA e. has a. group of tufts of bristles l eos-stief! the bristle body when viewed in side elevation presents a serrated or toothed appearance with a long tuft or tufts atthe tip end of the brush.

'In making my improved grinding wheel, I ilnd 5 it convenient to divide it into two parts, (l) the portion which grinds the tnft d at'the tip of the brush being made up of a series of discsin the weil known manner, and (2) the portion of the grinding wheel which grinds the remainder of the 10 bristle body. The surface of this blank is provided with a right hand and a left hand spiral groove each having in cross section a contour which varies from the contour of one of the tufts E seen inelevation to a dat or substantially fiat' 15 surface at a distance of l from. 'the starting point. Thus if point d, see Fig. 3, be considered as the starting point, the groove at this point has a contour of a width equal to the pitch of the spiral groove and also equal to the width of one of the 20 serrations E of the bristle body. The depth of the groove is equal to the height or depth4 of the tapering portion of the tuft. This is clearly seen in Fig. 4 4where the maximum depth of the groove is illustrated. This groove diminishes in depth 25 until at a distance of the surface becomes flat.- This will be readily understood from an examination of Fig. 5 which is a. section taken at 45 from Fig. 4, and shows that the groove has diminished to about one-half its original depthand in Fig. 6 30 which is a. section taken at $0 from Fig. 4 and shows that at this point the surface is entirely ilat, there beingno perceptible groove. After passing the 90 position. the situation is reversed, a groove makes its appearance and increases in 35 depth until the point 8 which is 180 from the starting point is reached. Thereafter the procedure described is repeated during the next There -is also 'a left-hand spiral groove i2 which starts at the other end of the conical 40' blank and crosses the right hand groove twice, in every 'revolution of the grinding wheel. This groove like the former alternately increases and diminishes in depth, the bottom of the groove becoming entirely flat when the two opposite 45 90 positions are reached. The grinding wheel, therefore, has two substantially nat or ungrooved areas f, f extending longitudinally of the wheel and located 180 from each other. This flat 5o strip is formed by the comparatively ilat bottom of the two grooves. Halfway between these two fiat areas are areas where the grooves have maximum or substantially maximum depth, these being 180 fromeach other and 90 from 55 theends of its bristles against the grinding wheel, the ends of several serrations fit into the respective grooves. The bristle forming one such serration is shown in Fig. 4 being located in a groove I3. It will be seen that the grinding surfaces of the groove are in contact with the sides of the ends of each ot the bristles. The

of each bristle contacting with the side portion o( bristles-in one position and withthe extreme lehdsein variotliier and'with the intermediate parts. of fthe bristles in the. intermediate positions.. The wheel, ltherefore, accomplishes a make my 10 than on the sides.

wheel can then be considered as revolving to the position shown in Fig. 5 the tutt' being still in the groove I3 but the groove has grown shallower and more of the end portion of each bristle is in contact with the grinding surface of the wheel I3. When the revolution of the wheel is continued to the position shown in Fig. 6 the ends of. the bristles rest against the flat area and are being ground on the ends of the bristles rather Further revolution of the wheel brings the ridge Il, see Fig. 7, up under the tufts of bristles dividing them in two parts so that thereafter the sides oi the bristles which have previously `not been in contact-with the wheel now contact with it. As the wheelrevolves the groove becomes deeper a'nd the grinding effect is more and more on the side or the bristle. l Y

It will be understood that by this means the grinding proceeds around and around the end or liquid bakelite kIn some cases, it is more i convenient to formthe entire wheel or the major portion of it from abrasive material. In Fig. 11,

I have shown a wheel the body of which I5 is bakelite, wood, or fibre and to which is applied 20 an abrasive coating I6. In Fig. 10, I have shown a wheel I1 which is made of solid grinding material.

What I claim is:

A Agrinding wheel formed of a body von the 25 surface of which are formed right and left'hand spiral grooves which cross each other at 180 intervals, said grooves alternately increasing and decreasing in depth through an angle of 180 and forming two ilat longitudinal bands 180 l0 apart, separated by two grooved bands whose maximum groove depth is 180 from each ot the iiat bands. WILLIAM S. ELLIOT.

to the body of the wheel by varnish, glue, shellac l5'\ 

